JP4644832B2 - Rotating electrical machine - Google Patents

Description

【Technical field】
[0001]
  The present invention relates to a rotating electric machine such as an electric motor (motor). In particular, the present invention relates to a so-called bearingless rotating machine that supports a rotor (rotor) with magnetic force and eliminates the need for a mechanical bearing such as a bearing.
[Background]
[0002]
  In general, there is an increasing demand for higher speed and higher output for an electric motor (motor) that is one of rotating electric machines used in machine tools, turbo molecular pumps, flywheels, and the like. So-called magnetic bearings are sometimes applied to solve problems such as limitations and maintenance.
[0003]
  A rotating electrical machine using magnetic bearings is called a bearingless rotating machine, and in such a bearingless rotating machine, there is one in which a magnetic bearing function and a motor function are realized by a single rotating electrical machine. . For example, Tadashi Fukao (President of the Institute of Electrical Engineers of 2003, Professor Emeritus of Tokyo Institute of Technology), Akira Chiba (Professor of Tokyo University of Science), “Bearingless Motor” Journal of the Institute of Electrical Engineers of Japan vol. 117, no. 9, PP. 612-615, 1997, and the book A. Chiba, T .; Fukao, O .; Ichikawa, M .; Oshima, M .; Takemoto and D.H. G. This is described in Dorrell, “Magnetic Bearings and Bearing Drives”, Elsevier Newness Press, ISBN 0-7506-5727-8, 2005, and the like.
[0004]
  In the bearingless rotating machine described in the above-mentioned document, the electromagnetic force in the biaxial direction of x and y in the radial direction and the torque for rotation are generated. Three-phase windings are provided, and a separate winding group is required to generate a radial electromagnetic force (this separate winding group is called a support winding). And a bearingless rotating machine implement | achieves a bearing function magnetically (in other words, implement | achieves the damping function of the main axis | shaft of a rotary electric machine).
[0005]
  Use of such bearingless rotating machines is expanding to pumps for semiconductor manufacturing equipment. When a bearingless rotating machine is used for a pump for semiconductor manufacturing equipment, the gap length between the rotor and the stator is designed to be larger than that of a normal rotating machine, and both torque and magnetic support force tend to decrease. .
[0006]
  In other words, in bearingless rotating machines used in chemical plants, the surfaces of the stator and rotor must be covered with partition walls, and the partition walls are made of Teflon (registered trademark) resin to maintain chemical resistance. There is a need to. For this reason, it is unavoidably necessary to increase the magnetic gap length between the stator core and the rotor core.
[0007]
  Furthermore, since a permanent magnet is used in the bearingless rotating machine, the attractive force at the time of eccentricity when the power is turned off is large. For this reason, it is necessary to start by generating an active (magnetic) supporting force larger than the attractive force of the permanent magnet. Thus, in the bearingless rotating machine, since the gap length is large, it is necessary to increase the magnetic support force.
[0008]
  On the other hand, the inventors have proposed a bearingless rotating machine described in Patent Document 1 having a large magnetic support force. FIG. 15 is a diagram showing a bearingless rotating machine described in Patent Document 1. As shown in FIG. In FIG. 15, the bearingless rotating machine has a rotating shaft (main shaft) 11, and two rotors 12 a and 12 b are coaxially mounted on the rotating shaft 11.
[0009]
  In FIG. 15, the repetition period of the protrusion 13a and the recessed part 13b in the rotor 12a is different from the repetition period of the protrusion 14a and the recessed part 14b in the rotor 12b by a half pitch. Two stators 15a and 15b are disposed outside the two rotors 12a and 12b so as to surround the two rotors 12a and 12b, respectively.
[0010]
  The two stators 15a and 15b have a radial force generating winding to which a current controlled by a current controller 16 is applied, and a torque generating winding to which a current controlled by a torque current controller 17 is applied. Lines are provided. A winding 18 used as a magnetomotive force generating means is mounted between the stator 15a and the stator 15b. A direct current is applied to the winding 18 to excite the two rotors 12a and 12b in the axial direction.
[0011]
  When the two rotors 12a and 12b and the two stators 15a and 5b are arranged in tandem in the axial direction across the winding 18 that excites the rotor in the axial direction, the two stators 15a and 15b It is desirable to arrange a magnetic casing 19 or the like that magnetically connects the outer peripheral portions of the magnetic body 15b (stator core). A permanent magnet or the like may be arranged instead of the casing 19 that connects the winding 18 and the outer periphery of the two stator cores.
[0012]
  Permanent magnets 20a and 20b are attached to the two rotors 12a and 12b at predetermined intervals along the circumferential direction, respectively. In FIG. 15, the polarities of the outer surfaces of the permanent magnets 20a in the rotor 12a are all N poles, and the polarities of the outer surfaces of the permanent magnets 20b in the rotor 12b are all S poles. In the two rotors 12a and 12b, the magnetic poles of the permanent magnets 20a and 20b are arranged so as to be shifted from each other by a half pitch. For example, if the number of magnetic poles of the two rotors 12a and 12b is 8 respectively, the circumferential position where the permanent magnets 20a and 20b are arranged differs by 45 degrees depending on the mechanical angle.
[0013]
  In the bearingless rotating machine shown in FIG. 15, the displacements of the total four axes in the radial direction of the two rotors 12a and 12b are detected by the radial position detectors 21a and 21b. Position data output from the pair of radial position detectors 21 a and 21 b is input to the position controller 23. The position controller 23 compares the radial displacement of the rotor indicated by the position data with the position command value and corrects the two rotors 12a and 12b to the positions indicated by the position command value. The current value of the winding 22 is calculated.
[0014]
  In FIG. 15, only the position control device for two radial axes of the two rotors is shown, and the position control device for two radial axes of the other rotor is omitted. ing.
[0015]
  A rotation angle detector 24 for detecting a rotation angle, such as a rotary encoder, and a rotation speed detector 25 for detecting the rotation speed are attached to the rotary shaft 11 and fed back to the motor controller 26 to drive as a synchronous motor. When driving the above-described bearingless rotating machine, the winding 18 for exciting the two rotors 12a and 12b arranged between the two stators in the axial direction is used for the core magnetic pole portion of the rotor. Change the magnetic flux. As a result, the induced electromotive force and power factor of the torque generating winding are adjusted, and the four radial directions of the rotor are supported in a non-contact manner and torque is generated.
[Patent Document 1]
JP-A-10-150755
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0016]
  By the way, the bearingless rotating machine described in Patent Document 1 has advantages such as the generation of a large magnetic supporting force for the current and the need for detecting the rotation angle at the time of control. Thus, the gap length of the rotor is large, and if this gap length becomes long, sufficient magnetic support force cannot be obtained. In addition, if the magnetic support force is not sufficient, the magnetic support force depends on the rotation angle of the rotor, so that there is a problem that it is not necessary to detect the rotation angle.
[0017]
  The present invention has been made in view of such problems, and an object of the present invention is to obtain a sufficient shaft support force (magnetic support force) even when the gap length of the rotor is large. An object is to provide a rotating electrical machine.
[Means for Solving the Problems]
[0018]
  (1) A rotary electric machine including a rotor and a stator, wherein the rotor includes a first rotor portion that generates torque or torque and supporting force, and a second rotor that generates supporting force. And the stator includes magnetomotive force generating means for generating radial force and torque with respect to the rotor, and the first rotor portion and the second rotor portion are: A rotating electrical machine characterized by being arranged in tandem.
[0019]
  (2) The first rotor portion includes a first rotor core and a permanent magnet mounted on the first rotor core or an induction conductor through which an induction current flows, and the second rotor portion is The rotary electric machine according to (1), further comprising a second rotor iron core.
[0020]
  (3) The rotating electric machine according to (2), wherein the first rotor portion has a contiguous pole structure.
[0021]
  (4) A plurality of the permanent magnets in the first rotor portion are provided, the first rotor core is cylindrical, and the permanent magnets are mounted on the surface or inside of the first rotor core and adjacent to each other. The rotating electric machine according to (2), wherein the outer surface in the radial direction of the permanent magnet is a different magnetic pole.
[0022]
  (5) The stator includes a first stator core and a second stator core, and the rotor includes a first rotor and a first stator corresponding to the first stator core and the second stator core, respectively. The first rotor and the second rotor each have a first rotor part and a second rotor part, and the first stator core and the second stator core are provided. And between the first rotor and the second rotor, a magnetic flux generating section that generates a magnetic flux in the axial direction is disposed on at least one of the first rotor and the second rotor (1) to ( 4) The rotating electrical machine according to any one of the above.
[0023]
  (6) The axial thicknesses of the first rotor and the second rotor are thicker than the axial thicknesses of the first stator core and the second stator core, respectively. 5) The rotating electrical machine described above.
[0024]
  (7) The stator includes a first stator core and a second stator core, and the rotor includes a first rotor and a second stator core respectively corresponding to the first stator core and the second stator core. Two rotors, the first rotor has the first rotor part and the second rotor part, the second rotor has the second rotor part, and the first rotor Between the stator core and the second stator core, and between the first rotor and the second rotor, a magnetic flux generator that generates a magnetic flux in the axial direction is disposed at least on one side. The rotating electrical machine according to any one of (1) to (4).
[0025]
  (8) The rotating electric machine according to (7), wherein an axial thickness of the second stator core is thicker than an axial thickness of the second rotor.
[0026]
  (9) The rotating electric machine according to (8), wherein the axial thickness of the first rotor is thicker than the axial thickness of the second rotor.
[0027]
  (10) In the first rotor portion of the first rotor, a first iron core salient pole portion and a first iron core concave portion to which a permanent magnet is attached are alternately and equally divided, and the second rotor is arranged. In the first rotor portion, the second core salient pole portion and the second core recess portion to which the permanent magnet is attached are alternately and equally divided, and the first core salient pole portion and the first core recess portion are arranged. Has a first cycle that repeats, and the second core salient pole portion and the second core recess have a second cycle that repeats the same as the first cycle, and the first rotor and the second The two-rotor is arranged so as to overlap the phase of the first period and the phase of the second period, or so that the mutual phases are slightly shifted from each other. machine.
[0028]
  (11) The rotor includes an outer rotor structure configured outside the stator, the rotor includes an inner rotor structure configured inside the stator, and the stator and the rotor include The rotating electrical machine according to any one of (1) to (9), including a disk-type structure facing each other.
【The invention's effect】
[0029]
  In the rotary electric machine according to the invention of (1), since the rotor has the second rotor portion that effectively generates the shaft support force, the shaft support force can be increased with respect to the drive current. The angular pulsation of the supporting force can be reduced. As a result, there is an effect that a sufficient shaft support force (magnetic support force) can be obtained even when the gap length of the rotor is large.
[0030]
  The rotating electrical machine according to the invention of (2) has a first rotor portion having a first rotor core and a permanent magnet mounted on the first rotor core or an induction conductor through which an induced current flows, and a second rotor. Since the part has the second rotor core, the torque can be effectively generated by the first rotor part, and the shaft support force can be effectively generated by the second rotor part.
[0031]
  The rotating electrical machine according to the invention of (3) has an effect that the torque and the shaft supporting force can be effectively generated because the first rotor portion has a contiguous pole structure.
[0032]
  In the rotating electrical machine according to the invention of (4), the first rotor portion is provided with a plurality of permanent magnets, the first rotor core is formed in a cylindrical shape, and the permanent magnet is mounted on or inside the first rotor core. Since the radially outer surfaces of the permanent magnets adjacent to each other are made to be different magnetic poles, the first rotor portion only generates torque, and the second rotor portion can obtain the shaft support force. is there.
[0033]
  In the rotating electrical machine according to the invention of (5), the stator includes first and second stator cores, and the rotor includes first and second rotors corresponding to the first and second stator cores. Each of the first and second rotors has first and second rotor portions, and is between the first stator core and the second stator core and between the first rotor and the second rotor. Since a magnetic flux generator that generates a magnetic flux in the axial direction is disposed in at least one of them, the effect that the two radial (radial directions) axes can be actively controlled by the first and second rotor parts, respectively. There is.
[0034]
  In the rotary electric machine according to the invention of (6), since the axial thicknesses of the first and second rotors are larger than the axial thicknesses of the first and second stator cores, respectively, the gap length is large. In this case, even if a large amount of fringing magnetic flux is generated in the axial direction, since the thickness (axial length) of the first and second rotor parts is long, the fringing magnetic flux can be effectively used to generate torque and shaft support force. There is an effect.
[0035]
  In the rotating electrical machine according to the invention of (7), the stator includes first and second stator cores, and the rotor includes first and second rotors corresponding to the first and second stator cores. The first rotor has first and second rotor parts, the second rotor has a second rotor part, between the first stator core and the second stator core, and Between the first rotor and the second rotor, a magnetic flux generator that generates a magnetic flux in the axial direction is disposed on at least one of the first and second rotors, so that there is an effect that control is possible not only in the radial direction but also in the thrust direction. .
[0036]
  The rotating electrical machine according to the invention of (8) has an effect that the displacement in the thrust direction can be braked because the axial thickness of the second stator core is made thicker than the axial thickness of the second rotor. .
[0037]
  In the rotary electric machine according to the invention of (9), since the axial thickness of the first rotor is made larger than the axial thickness of the second rotor, torque is effectively generated and the thrust rotor is moved in the thrust direction. There is an effect that the displacement can be braked.
[0038]
  Since the rotating electrical machine according to the invention of (10) is arranged so that the phase of the first rotor and the phase of the second rotor overlap each other, the radial direction (radial direction) by the first and second rotor portions, respectively. ) In addition to the effect that the two axes can be actively controlled, there is an effect of reducing pulsation by arranging the phases slightly shifted from each other.
[0039]
  The rotating electrical machine according to the invention of (1) includes an outer rotor structure in which the rotor is configured outside the stator, and includes an inner rotor structure in which the rotor is configured inside the stator, and the stator and the rotor Since the disk-type structure facing each other is included, there is an effect that the application range is wide.
[0040]
  The rotating electrical machine according to the present invention has an effect that a sufficient shaft supporting force can be generated even when the gap length is large.
[Brief description of the drawings]
[0041]
FIG. 1 is a perspective view showing an example of a rotor used in a bearingless motor according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a rotor according to the embodiment.
FIG. 3 is a configuration diagram illustrating a principle of generating a shaft support force of a bearingless motor according to the present invention.
FIG. 4 is a configuration diagram illustrating the principle of generating a shaft support force of a bearingless motor according to the present invention.
FIG. 5 is a perspective view showing another example of the structure of the rotor used in the bearingless motor which is an example of the rotating electric machine according to the embodiment of the present invention.
FIG. 6 is a diagram showing four-axis active control in a bearingless motor which is an example of a rotating electric machine according to an embodiment of the present invention.
7 is a longitudinal sectional view showing a modification of FIG.
8 is a longitudinal sectional view for explaining displacement braking of a rotating shaft in FIG. 7. FIG.
FIG. 9 is a diagram showing a first example of the arrangement of stator core teeth and permanent magnets in a bearingless motor which is an example of a rotating electrical machine according to an embodiment of the present invention.
FIG. 10 is a diagram showing a second example of the arrangement of stator core teeth and permanent magnets in a bearingless motor that is an example of a rotating electrical machine according to an embodiment of the present invention.
FIG. 11 is a diagram showing a third example of the arrangement of stator core teeth and permanent magnets in a bearingless motor which is an example of a rotating electrical machine according to an embodiment of the present invention.
FIG. 12 is a diagram showing a fourth example of the arrangement of stator core teeth and permanent magnets in a bearingless motor that is an example of the rotating electrical machine according to the embodiment of the present invention.
13 is a perspective view illustrating another example of a rotor including two rotors having a configuration different from that of the rotor including two rotors illustrated in FIG. 6. FIG.
14 is a perspective view of a bearingless rotating machine that is an example of a rotating electric machine according to an embodiment of the present invention using the rotor shown in FIG. 13, and shows a core salient pole part in section.
FIG. 15 is a perspective view for explaining a conventional bearingless motor.
[Explanation of symbols]
[0042]
  11 Rotating shaft (spindle)
  31 ・ 41 ・ 81 Rotor
  32, 42, 55 1st rotor part
  33, 56, 61 Second rotor part
  32a, 42a Rotor core
  32b ・ 42b ・ 72 Permanent magnet
  32c Iron core salient pole
  32d rotor yoke
  32e Iron core recess
  51 First rotor
  52 Second rotor
  53 First stator core
  53a ・ 54a Stator winding
  54.62 2nd stator core
  73 Stator
  57 Permanent magnet between rotors
  58 ・ 82 Permanent magnet between stators
BEST MODE FOR CARRYING OUT THE INVENTION
[0043]
  A bearingless motor, which is an example of a rotating electrical machine according to an embodiment of the present invention, will be described below with reference to the drawings. Here, since the structure of the rotor is different from the two rotors 12a and 12b described in FIG. The overall configuration of the brushless motor is the same as that shown in FIG.
[0044]
  FIG. 1 is a perspective view showing an example of a rotor 31 used in a bearingless motor according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the rotor 31 shown in FIG. 1 and 2, the rotor 31 has first and second rotor portions 32 and 33, and the first and second rotor portions 32 and 33 are coaxially arranged at the center thereof. A rotating shaft (main shaft) 11 is inserted. The first and second rotor portions 32 and 33 are arranged in tandem on the rotating shaft 11 (the rotating shaft 11 is omitted in FIG. 1).
[0045]
  In FIG. 1, the 1st rotor part 32 has the permanent magnet 32b with which the predetermined | prescribed space | interval was mounted | worn along the circumferential direction of the rotor core 32a. In the embodiment of FIG. 1, four permanent magnets 32b are mounted. In the embodiment of FIG. 1, all the polarities of the outer surface of the permanent magnet 32b are N poles. The rotor core 32a is formed by stacking, for example, silicon steel plates punched out like salient poles, and a permanent magnet 32b is fixed to a recess formed in the rotor core 32a. As described above, the permanent magnet 32b is magnetized in the same direction (N pole in the example of FIG. 1) on the outer side (outer surface).
[0046]
  As a result, magnetic flux is generated from the outside of the permanent magnet 32b, passes through the stator (not shown) through the gap, passes through the gap again, and returns to the core salient pole portion 32c which is a part of the rotor core 32a. Further, it returns to the inside of the permanent magnet 32b through the rotor yoke 32d which is a part of the rotor core 32a.
[0047]
  For this reason, the iron core salient pole portion 32c is magnetized to the opposite pole (in this case, the S pole) to the permanent magnet 32b, and constitutes an 8-pole rotor (such a rotor is a continuous pole type). That is, in the illustrated example, the first rotor portion 32 is a continuous pole type rotor). Then, torque is generated by interaction with an 8-pole motor winding (torque generating winding) provided on the stator. Further, a radial force (shaft support force) is generated by interaction with a two-pole shaft support winding (radial force generating winding) provided on the stator. That is, the stator includes an electric motor winding and a shaft support winding that are magnetomotive force generating means for generating radial force and torque with respect to the rotor 31.
[0048]
  Next, the generation principle of the shaft support force in the first rotor portion 32 will be described with reference to FIG. 3 and FIG. 4. FIG. 3, the pole field magnetic flux Ψ by the permanent magnet 32b._8mAnd 2-pole shaft support winding N_s2β1Current i_s2β1To support the shaft support magnetic flux Ψ_s2β1Will occur. Ψ_s2β1Passes through the core part between the magnets having a small magnetic resistance, and escapes from the lower side of the rotor to the upper side.
[0049]
  As a result, in the gap above the rotor, Ψ_8mAnd Ψ_s2β1Strengthen each other and weaken each other in the lower gap, and the rotor (first rotor portion 32) has a shaft support force F in the positive direction of the β axis, which is the sparse to dense direction of the magnetic flux._βWill occur.
[0050]
  Similarly in FIG. 4 where the rotation angle θ = 45 deg, N_s2β1Current i equal to_s2β1, The shaft support force F of the same magnitude as the β axis positive direction_βWill occur. Therefore, the shaft support force is constant regardless of the rotation angle θ and can be controlled by a direct current.As will be described later, strictly speaking, the shaft support force F _β Slightly pulsates as the rotor rotates.
[0051]
  By the way, in the 1st rotor part 32, ie, a continuous pole type | mold rotor, since the magnetic pole by the permanent magnet 32b and an iron core pole exist, in fact, the axial support force which generate | occur | produces with rotation of a rotor. The magnitude and direction of (magnetic support force) pulsates, and furthermore, only the iron core pole generates a shaft support force (magnetic support force), so that the shaft support force decreases.
[0052]
  For this reason, in the illustrated example, the second rotor portion 33 is inserted through the rotating shaft 11 after the first rotor portion 32 in order to improve the shaft support force. The second rotor portion 33 is a support force generating rotor. When the axial length (axial thickness) of the first rotor portion 32 is L1, and the axial length of the second rotor portion 33 is L2, L1. > L2. Here, the first rotor portion 32 is sometimes called a torque generating rotor. However, as described above, the first rotor portion 32 is a continuous pole type rotor, and thus not only generates torque. Also, support force is generated.
[0053]
  The second rotor portion 33 generates an electromagnetic force by interaction with a current flowing in a radial force generating winding (shaft supporting winding) or a supporting force / torque generating winding wound around the stator. To do. When the first rotor portion 32 is a continuous pole type or a homopolar type, for example, a rotor having a cylindrical shape formed by laminating disk-shaped silicon steel plates in the axial direction is used as the second rotor portion 33. The second rotor portion 33 is excited to the same polarity as the iron core pole of the first rotor portion 32 by a permanent magnet 32b or a field winding. In the illustrated example, the second rotor portion 33 is excited to the S pole.
[0054]
  As a result, the second rotor portion 33 generates a shaft support force in the same manner as the support force generation principle described for the first rotor portion 32 described above. As a result of the cylindrical shape of the second rotor portion 33, the shaft support force does not pulsate in the magnitude and direction of the electromagnetic force. Furthermore, as a result of the absence of permanent magnets in the second rotor portion 33, all of the cylindrical shape contributes to the generation of the shaft support force, and the shaft support force can be improved. That is, a sufficient shaft support force can be obtained even when the gap length is large.
[0055]
  In other words, since there is no permanent magnet in the second rotor portion 33, torque is not generated, but the shaft support force can be increased, and the second rotor portion 33 is cylindrical, Even if the rotation angle of the two-rotor portion 33 changes, no pulsation occurs in the direction and magnitude in which the shaft support force is generated. As a result, a decrease in shaft support force and pulsation of the shaft support force in the first rotor portion 32 can be reduced.
[0056]
  In the illustrated example, L1> L2, but L1 and L2 are appropriately changed according to the purpose of use of the bearingless motor.
[0057]
  FIG. 5 is a perspective view showing another embodiment of the rotor. The rotor shown in FIG. 5 has a structure different from that of the rotor 31 described with reference to FIG. In addition, the same reference number is attached | subjected about the component same as the rotor 31 shown in FIG. In FIG. 5, the structure of the first rotor portion is different from that of the first rotor portion 32 described in FIG. In FIG. 5, the first rotor portion 42 has a cylindrical rotor core 42a. The rotor core 42a is formed by stacking, for example, silicon steel plates.
[0058]
  In FIG. 5, a plurality of permanent magnets 42b are attached to the surface of the rotor core 42a so as to cover the entire surface of the rotor core 42a. In FIG. 5, a total of eight permanent magnets 42b are attached to the surface of the rotor core 42a, and the surfaces of the adjacent permanent magnets 42b have different magnetic poles.
[0059]
  The first rotor portion 32 described in FIG. 1 is a continuous pole type rotor, but the first rotor portion 42 shown in FIG. 5 has a structure in which a permanent magnet 42b is attached to the surface of the rotor core 42a. (That is, because the core salient pole is not formed (because it is a rotor having an SPM structure)), no magnetic support force is generated in the first rotor portion 42. That is, only the torque is generated in the first rotor section 42 shown in FIG. 5, and as a result, a larger torque can be generated as compared with the continuous pole type rotor.
[0060]
  In FIG. 5, the number of poles of the first rotor portion 42 is eight, but the number of poles may be an integer such as 1, 2, 3, 4, 5, 6, and the like. In the type rotor, in order to reduce the pulsation of the generation of the shaft support force accompanying the rotation, the number of poles needs to be 6 or more, but the shaft support force is the second rotor portion 33 (support force generation rotation). In the rotor 41 shown in FIG. 5, the number of poles of the first rotor portion 42 is arbitrary.
[0061]
  Further, there is a possibility that electromagnetic force is generated by the interaction between the shaft support winding and the first rotor portion 42 (torque generating rotor), but this point can be reduced by using the thick permanent magnet 42b. And if the ratio of the 2nd rotor part 33 (supporting force generation | occurrence | production rotor) is enlarged (that is, L2> L1), since electromagnetic force is reduced relatively, there is no problem.
[0062]
  Referring to FIG. 6, here, as described in FIG. 15, there is shown an example in which two first and second rotors 51 and 52 are mounted on the rotating shaft 11, and the first and second rotations are shown. First and second stator cores 53 and 54 are disposed outside the cores 51 and 52 so as to surround the first and second rotors 51 and 52, respectively, with a gap. The first and second stator cores 53 and 54 are respectively provided with stator windings 53a and 54a (torque generating windings, shaft supporting force generating windings, CE indicates a coil end), A permanent magnet 58 between the stators is disposed between the first and second stator cores 53 and 54. A permanent magnet 58 between the stators generates an axial magnetic flux.
[0063]
  On the other hand, the two first and second rotors 51 and 52 use the rotor described in FIG. 1 or the rotor described in FIG. 5, and the two first and second rotors 51 and 52. Both have first and second rotor portions 55 and 56. A permanent magnet 57 between the rotors is disposed between the two first and second rotors 51 and 52, and the two first and second rotations are performed by the permanent magnet 57 between the rotors. The children 51 and 52 are magnetized in the axial direction.
[0064]
  The permanent magnets 57 between the rotors may be omitted and only the permanent magnets 58 between the stators may be omitted, or the permanent magnets 58 between the stators may be omitted and only the permanent magnets 57 between the rotors. Here, each of the permanent magnet 58 between the stators and the permanent magnet 57 between the rotors is a magnetic flux generation unit.
[0065]
  In the illustrated example, the axial length Ls of the first stator core 53 (or the second stator core 54) <the axial length Lr of the first rotor 51 (or the second rotor 52). The axial length Lr of the rotor and the axial length Ls of the stator may or may not be equal. In addition, about the coil end (CE) between the two first and second stator cores 53 and 54, the coil is wound across the two first and second stator cores 53 and 54. This can be omitted.
[0066]
  In the example shown in FIG. 6, two first and second rotors 51 and 52 are used. Therefore, the first rotor 51 has two left and right rotors in the radial direction (radial direction) in the drawing. Therefore, the two radial axes at the right end in the figure can be actively controlled.
[0067]
  Although not shown, in the same manner as a normal 4-axis active control bearingless motor, the displacement of the rotating shaft is obtained by an electronic circuit that detects the displacement of the rotating shaft or estimates the displacement of the rotating shaft, and responds to this displacement. The controller then calculates the current that gives the damping force, and supplies the current to the shaft support winding or dual-purpose winding. Thus, if feedback control is performed on the displacement of the rotating shaft, a four-axis active control type bearingless motor can be configured.
[0068]
  In FIG. 6, only the upper half (a part) of the two first and second stator cores 53 and 54 is shown for simplification, but as described above, the two first and second stator cores 53 and 54 are shown. The second stator cores 53 and 54 are disposed so as to surround the two first and second rotors 51 and 52. In addition, FIG. 6 shows an example in which two first and second rotors 51 and 52 are inserted through the rotating shaft 11, but a single rotor is used as a continuous pole type bearingless motor. There may be a two-axis active control type. The bearingless motor may include an outer rotor structure motor in which the rotor is configured outside the stator, and may include a disk type motor in which the stator and the rotor face each other.
[0069]
  7 is a cross-sectional view showing a modification of the example described with reference to FIG. 6. In FIG. 7, the same components as those in the example shown in FIG. In the example shown in FIG. 7, the second rotor portion 61 has an axial length Lr2 that is sufficiently shorter than the axial length Lr1 of the first rotor 51, and the second rotor portion 61 has an axial support force. Has only a single function of generation. For example, the second rotor portion 61 is a passive magnetic bearing as a magnetic disk. In addition, in the example shown in FIG. 7, you may arrange | position the permanent magnet 57 between rotors (refer FIG. 6).
[0070]
  Regarding the effects of passive magnetic bearings, for example, Kazuyoshi Asami, Akira Chiba, Ken Hoshino, Atsushi Nakajima “Bearingless Motor for 2-Axis Control Flywheel” The 48th Space Science and Technology Conference Lecture Meeting 1F07 pp. 411-416 2004.11.4-6 Phoenix Plaza Fukui.
[0071]
  Further, as shown in FIG. 7, the second stator core 62 corresponding to the second stator core 54 described in FIG. 6 is sufficiently shorter than the axial length of the first stator core 53. The second stator core 62 and the second rotor portion 61 are opposed to each other. The axial length of the second stator core 62 is longer than the axial length of the second rotor portion 61.
[0072]
  Referring also to FIG. 8, in the example shown in FIG. 7, the permanent magnet 58 between the stators is magnetized to the N pole on the second stator core 62 side. And the S pole appears on the surface of the second rotor portion 61. As described above, since the axial length of the second stator core 62 is longer than the axial length of the second rotor portion 61, the magnetic lines of force from the second stator core 62 are concentrated on the second rotor portion 61. As a result, the magnetic flux density increases in the vicinity of the second rotor portion 61.
[0073]
  As a result, when the rotating shaft 11 moves in the direction indicated by the broken line arrow in FIG. 8, the magnetic field lines are bent (distorted) on the left side in the drawing, and a force acts in the direction indicated by the solid line arrow F in the drawing, 11 is returned to the original position.
[0074]
  Further, as shown by a double circle in FIG. 7, a winding 63 is provided between the first stator core 53 and the second stator core 62 so that the amount of magnetic flux in the axial direction is controlled by current. Thus, a thrust force can be generated, and the displacement in the thrust direction can be actively controlled. In addition, a thrust bearing may be provided separately. In FIG. 8, only one disk as the second rotor portion 61 is shown, but a plurality of disks may be configured in multiple stages. At this time, the second rotor portion 61 and the second stator core 62 are arranged to face each other.
[0075]
  9 is a view showing an example in which a permanent magnet 72 (this permanent magnet 72 corresponds to the permanent magnet 58 between the stators shown in FIG. 7) is disposed on the stator core 71. As shown in FIG. These are the figures which looked at the stator 73 from the axial direction. The stator core 71 has a stator protrusion (stator core teeth) 71a and a yoke 71b, and the stator core teeth 71a are formed at a predetermined angular interval. A permanent magnet 72 is disposed in the yoke 71b at the root of the stator core teeth 71a (that is, a recess is formed in the yoke 71b corresponding to the stator core teeth 71a, and the permanent magnet 72 is provided in the recess. Arranged).
[0076]
  Normally, in a stator, a cylindrical permanent magnet is disposed on the yoke so as to cover the entire yoke, but it is easier to mold a rectangular parallelepiped permanent magnet than to mold a cylindrical permanent magnet. For this reason, as shown in FIG. 9, if the permanent magnet 72 is disposed on the yoke 71b at the root of the stator core tooth 71a, the rectangular permanent magnet 72 is disposed, and the permanent magnet to be used. Can be optimally adjusted.
[0077]
  In FIG. 10, at the base of the stator core tooth 71a, the bottom surface of the recess formed in the yoke 71b is tapered. If the taper 74 is provided in this way, the volume of the recess is substantially increased, and a larger permanent magnet 72 can be used.
[0078]
  FIG. 11 shows that the concave portion formed in the yoke 71b at the base of the stator core teeth 71a has a square shape (for example, a rectangular parallelepiped shape), and the square (rectangular shape) permanent magnet 72 is easily attached to the yoke 71b. It can be arranged.
[0079]
  FIG. 12 is an example in which a concave portion is formed in the yoke 71b over the roots of two adjacent stator core teeth 71a, and a permanent magnet 72 is disposed in the concave portion. In this example, in the stator core teeth 71a, FIG. Not only can magnetic saturation be reduced (that is, not only can the magnetic resistance be reduced to effectively generate magnetic flux), but also a larger permanent magnet 72 can be provided.
[0080]
  FIG. 13 shows a rotor including two first and second rotors 31a and 31b having a different configuration from the rotor including the two first and second rotors 51 and 52 shown in FIG. FIG. Referring to FIG. 13, the rotor 81 has two first and second rotors 31a and 31b arranged coaxially. The first rotor 31a and the second rotor 31b are a first rotor part 32 that is a contiguous pole type rotor, and a second rotor that is connected to the first rotor part 32 and generates a shaft support force. It is comprised with the part 33 (refer FIG. 1). Here, the first and second rotors 31a and 31b are structurally the same as the rotor 31 shown in FIG. 1, but are distinguished by changing the reference numerals for convenience of explanation.
[0081]
  As shown in FIG. 13, in the rotor 81, the first rotor part 32 of the first rotor 31a and the first rotor part 32 of the second rotor 31b are arranged in opposite directions. The permanent magnet 32b attached to the first rotor portion 32 of the first rotor 31a is magnetized in the S-pole in the radial direction facing the stator. On the other hand, the permanent magnet 32b attached to the first rotor portion 32 of the second rotor 31b is magnetized with an N pole in the radial direction facing the stator. In the embodiment shown in FIG. 13, each of the first rotor 31a and the second rotor 31b has four permanent magnets 32b. However, the permanent magnets 32b may be arranged with one or more integers. That's fine.
[0082]
  In FIG. 13, the first rotor portion 32 of the first rotor 31a has first iron core salient pole portions 32c and first iron core recesses 32e on which permanent magnets 32b are mounted alternately and equally divided. Yes. Similarly, in the first rotor portion 32 of the second rotor 31b, the second iron core salient pole portion 32c and the second iron core concave portion 32e to which the permanent magnet 32b is attached are alternately and equally arranged. .
[0083]
  In FIG. 13, the first iron core salient pole portion 32c and the first iron core recess 32e have a first cycle that repeats. The second core salient pole portion 32c and the second core recess 32e have a second period that repeats in the same manner as the first period. The first rotor 31a and the second rotor 31b are arranged so as to overlap the phase of the first period and the phase of the second period, or so that their phases are slightly shifted from each other.
[0084]
  FIG. 14 is a perspective view of a bearingless rotating machine using the rotor 81 shown in FIG. 13, and shows the iron core salient pole portion 32c in cross section. In FIG. 14, as in FIG. 6, the first and second stators 31a and 31b are surrounded by the first and second stators so as to surround the first and second rotors 31a and 31b, respectively. Iron cores 81a and 81b are provided. A permanent magnet 82 between the stators is disposed between the first and second stator cores 81a and 81b. Axial thrust flux Ψ by permanent magnet 82 between the stators_sCan be generated. In addition, the permanent magnet between the 1st and 2nd rotor 31a * 31b is abbreviate | omitting illustration.
[0085]
  Referring to FIGS. 13 and 14, as in the conventional bearingless rotating machine shown in FIG. 15, the repetition period of the core salient pole part and the iron core concave part in one rotor is the same as that in the other rotor. It can be seen that there is no need to make a difference between the repetition period and the half pitch between the pole part and the iron core recess.
[0086]
  The rotating electric machine shown in FIG. 14 is arranged so that the phase of the first rotor 31a and the phase of the second rotor 31b overlap each other, so that the first and second rotor portions 32 and 33 respectively In addition to the effect that the two axes in the radial direction (radial direction) can be actively controlled, there is an effect of reducing pulsation by arranging the phases slightly different from each other.
[0087]
  In the above-described embodiment, the example in which the first rotor portion is a contiguous pole type or SPM structure has been described. However, the structure of the first rotor portion may be a cylindrical permanent magnet structure, a Halbach structure, or a surface attachment. Type permanent magnet structure, inset type permanent magnet structure, homopolar type, IPM type (permanent magnet built-in type), induction machine type (inductive current flows through conductors such as copper and aluminum formed in the rotor by a rotating magnetic field, torque Can be employed) or a reluctance type.
[0088]
  In other words, when a part of the rotor is the second rotor part that generates only the shaft support force, the generation of the shaft support force in the rotor part (first rotor part) that generates torque may be reduced. . Rather, it is better to generate torque effectively even if the shaft support force is reduced. For this reason, the above-mentioned various rotating machine structures can be applied to the first rotor portion.
[0089]
  Furthermore, the bearingless rotating machine described in the embodiment includes, for example, a generator such as a micro gas turbine, a flywheel motor generator, a pump, a blood pump, a blower, a compressor drive, an air conditioner, a household appliance, and a computer device. It is used for driving, automobile turbo generator motors, bioreactors, semiconductor manufacturing equipment, motors in vacuum vessels, special gas or liquid motors, and is controlled by the controller.

Claims (4)

A rotary electric machine comprising: a rotor; and a stator disposed opposite to the rotor and generating a rotational force to the rotor and a stator configured to generate a shaft support force. ,
An iron core, a first rotor part having a plurality of permanent magnets provided on the outer periphery of the iron core, and a second rotor part consisting only of the iron core, the first rotor part and the second rotor part, Two rotors having the same outer diameter and integrally formed are arranged at a predetermined interval,
Each of the two rotors is provided with a stator corresponding to each,
Rotating electricity characterized in that a ring-shaped permanent magnet is provided between the stators provided corresponding to the two rotors and between the two rotors to enhance the shaft support force. machine. The ring-shaped permanent magnets provided between the stators provided corresponding to the two rotors and between the two rotors are magnetized with opposite polarities in the rotation axis direction. The rotating electric machine according to claim 1. The plurality of permanent magnets provided on the outer peripheral part of the iron core are arranged such that the outer peripheral side of the first rotor part has the same polarity and is embedded in the iron core with a certain interval. The rotary electric machine according to claim 1 or 2 . The plurality of permanent magnets provided on the outer peripheral portion of the iron core are arranged so as to alternately change the polarities on the outer peripheral side of the second rotor portion and to form adjacent rings. The rotary electric machine according to claim 1 or 2 .

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